Individual correcting system for the electronically controlled electromagnetic injectors in internal combustion engines

ABSTRACT

The invention provides an individual correction of the duration of the injection of fuel into any one of the injectors of an internal combustion engine. To this end the signals generated by electronic control means and fed into the solenoid controlling injectors are diverted into a circuit connected across the terminals of the solenoid and including in series an adjustable impedance such as a resistance which may be in parallel with an adjustable capacitance and at least one diode the direction of which defines whether the lag is obtained for the opening or for the closing of the injector. A preferred embodiment of said circuit includes a resistance connected with the slider of a potentiometer the ends of which are connected with diodes connected in opposite directions and in parallel in the circuit so that according to the position of the slider the lag-producing action is predominantly that of one or the other diode.

I United States Patent 1151 3, 59,563

Monpetit [4 1 May 2, 1972 541 INDIVIDUAL CORRECTING SYSTEM 2,991,396 7/1961 Schurr ..317/DIG. 6

FOR THE ELECTRONICALLY CONTROLLED ELECTROMAGNETIC PUBL'CATONS INJECTORS IN INTERNAL Electronics World, May l967, Arc, Surge, & Noise Suppression by R. M. Rovnyak (pages 46-48 [72] Inventor: Louis A. Monpetit, LEtang-La-Ville, Primary Ex miner-Laurence M. Goodridge France Attorney-Kenyon & Kenyon Reilly Carr & Chapin [73] Assignee: gag-etc :ies Procedes Modernes dlnjectlon [57] ABSTRACT om The invention provides an individual correction of the dura- [221 Wed: July 1970 tion of the injection of fuel into any one of the injectors of an [21] APPL 53,342 internal combustion engine. To this end the signals generated by electronic control means and fed into the solenoid controlling injectors are diverted into a circuit connected across Foreign Pl i rity ial the terminals of the solenoid and including in series an ad- Aug 1 1969 France 6926492 justable impedance such as a resistance which may be in parallel with an adjustable capacitance and at least one diode the 1 CI I l l I I l l I I I U 3 l direction of defines whether the lag is obtained for the I 5 I] Int. Cl Fo'zm 52/00 opening or for the closing of the injector. A preferred embodi- [58] Field 32 EA ment of said circuit includes a resistance connected with the UIDIG 6 l 3 l slider of a potentiometer the ends of which are connected with diodes connected in opposite directions and in parallel in the 56] References Cited circuit so that according to the position of the slider the lagproducing action is predominantly that of one or the other UNITED STATES PATENTS diode- 3,448,728 6/ l 969 2 Claims, 4 Drawing Figures Scholl ..l23/l 19 X Patented May 2, 1972 2 Sheets-Sheet l INVENTQR Log/s MON ET/T 5v Z i 2% 2 ATTORn/EXS Patented May 2, 1972 3,659,563

2 Sheets-Sheet 2 //v VENTOF? Lou/.5 MONPET/T INDIVIDUAL CORRECTING SYSTEM FOR THE ELECTRONICALLY CONTROLLED ELECTROMAGNETIC INJECTORS IN INTERNAL COMBUSTION ENGINES The present invention has for its object an individual electric system for the correction of the amount of fuel injected into each electromagnetic injector controlled by a signal supplied by electronic control means.

It is a known fact that electromagnetic injectors for internal combustion engines from comparatively simple arrangements comprising a solenoid provided with its stationary armature extending within the body of the injector while a movable armature is rigid with the injector needle cooperating with its seat so as to control the opening and closing of the injection port as provided by the signals produced by the electronic control means. The needle is generally urged back against its seat by a spring and although such injectors seem to be simple it is a difficult matter to obtain perfect identity of design and operation between them. In fact, the amounts of fuel to be injected which are small should be measured with a high accuracy within a comparatively short time while the rising movement of the needle extends over only about 0.1 mm. Obviously under such conditions, the grade of the magnetic sections, the allowances in the mechanical parts, the clamping of the parts upon assembly of the injectors and the clamping of the injectors when fitted in position may exert an action on the accuracy of the injection.

It has already been proposed in my US. Pat. No. 3,456,628 to obtain said correction by acting on the duration of the control signal for each injector individually, by inserting a variable resistance and a diode between the input terminal of each injector and the delaying means. Although such an arrangement is satisfactory for certain-engines and injectors, it should be remarked that such a correction is of a multiplying character; in other words, it extends or shortens by a common coefficient the duration of the control signals independently of the length of said signals. Consequently, it cannot serve in all cases since it frequently occurs that it is necessary to apply an additive correction extending or shortening the duration of the control signal by a constant value independently of the duration of the signal fed by the delaying means. It may also be of interest to add or subtract such a correction at the beginning and/or at the end of the control signal or again it is possible to associate such an addition or subtraction with a multiplying correction such as that referred to hereinabove.

The present invention has for its object to solve such problems and it covers an individual electric circuit correcting the amount of fuel injected by each injector, said circuit including in parallel with the injector solenoid a variable impedance or two variable impedances in parallel, said impedance arrangement being connected in series with a diode or with two diodes in parallel.

As a development of this principle, it is possible to connect the diode in a direction such as to ensure a partial shunting of the feed current passing through the solenoid with a view to providing a lag in the opening of the injector.

According to a modification and in order to delay the closing of the injector, the diode may be connected in the opposite direction so as to ensure a partial shunting of the break-induced current.

According to a still further embodiment of the invention, the resistance is associated with a potentiometer the slider of which is connected with one of the terminals of the injector solenoid while each terminal of the resistance forming the potentiometer is connected with the other terminal of the solenoid through a corresponding diode, one of said diodes ensuring a shunting of the feed current while the other diode ensures a shunting of the break-induced current in a manner such that, according to the position of the potentiometer slider, the correction is performed predominantly at the beginning of the injection or conversely at its end.

By way of example and in order to further the understanding of the invention, there is illustrated in the accompanying drawings an embodiment of the invention and of various circuits associated therewith to be described hereinafter. In said drawings:

FIG. I is a block diagram of the arrangement of the electronically controlled injection means incorporating correcting systems according to the invention.

FIG. 2 is a detail of an electric correcting circuit according to a first embodiment.

FIG. 3 is a detail of an electric correcting circuit according to a first modification.

FIG. 4 is a detail of an electric circuit according to a further modification.

As illustrated, it is apparent that the engine 1 is provided in its admission manifold 51 with electromagnetically controlled injectors 4 fed with fuel under constant pressure by the pump 50 sucking fuel out of the container 46. The feeding of fuel is performed through a filter 49 associated with a pressure regulator 48 and a pressure accumulator 47 A signal generator 2 associated with the rotation of the engine feeds signals to control means 5 each time an injection is to be executed. Said control means 5 are fed with current by the battery 53 through the switch 52 and produce an injectioncontrolling signal the duration of which depends on the operative parameters of the engine, said duration defining the amount of fuel injected. The signals are applied to the injectors through the agency of a distributor 3 controlled by the rotation of the engine, of power means 9 and of the individual correcting means 6.

In FIG. 2 there is illustrated the solenoid 4a controlling an injector and correcting means 6, comprising diode 7, and adjustable resistance 8 in parallel with adjustable capacitance l1. Either of the components 8 and 11 may be used alone if required. In FIG. 2, the direction in which diode 7 is connected ensures partial shunting of the current feeding the injector so as to produce a lag in the opening of the injector.

In FIG. 3 the direction of connection of the diode 7 is the reverse of that in FIG. 2 and it ensures a shunting of a fraction of the break-induced current whereby a lag is obtained for the closing of the injector. I

The electric circuit according to the invention is executed advantageously as a unit in which the desired connections may be made just before operation so as to connect the diode in the desired direction while the adjustable components are adjusted.

Both corrections may be associated as illustrated in FIG. 4 in which the resistance 8 is connected with a potentiometer 10 while the diodes 7a and 7b connect the corresponding terminals of said potentiometer 10 with the terminal of the solenoid opposite to that connected with the resistance 8 so that the position of the potentiometer slider may lead to a correction producing predominantly a lag for the beginning or for the end of the injection.

What I claim is:

1. In an internal combustion engine having at least one electromagnetic fuel injector and a solenoid for actuating said injector in response to control signals of duration corresponding to the desired amount of fuel to be injected, an improved electric circuit for correcting the amount of fuel injected during each control signal comprising:

a. an adjustable impedance connected across said solenoid and b. a diode connected in circuit with said adjustable impedance across said solenoid in a direction such that it shunts a portion of the solenoid energizing current to thereby delay opening of the injector.

2. In an internal combustion engine having at least one electromagnetic fuel injector and a solenoid for actuating said injector in response to control signals of duration corresponding to the desired amount of fuel to be injected, an improved electric circuit for correcting the amount of fuel injected during each control signal comprising:

a. a first resistance, one end of which is connected to one terminal of the solenoid;

second resistance and the other terminal of the solenoid in a direction opposite to that of the first diode such that it shunts a portion of break-induced current in the solenoid to delay closing of the injector, the relative amount of opening and closing delay being determined by the position of the slider relative to the two ends of the second resistance.

i l 1 i 

1. In an internal combustion engine having at least one electromagnetic fuel injector and a solenoid for actuating said injector in response to control signals of duration corresponding to the desired amount of fuel to be injected, an improved electric circuit for correcting the amount of fuel injected during each control signal comprising: a. an adjustable impedance connected across said solenoid and b. a diode connected in circuit with said adjustable impedance across said solenoid in a direction such that it shunts a portion of the solenoid energizing current to thereby delay opening of the injector.
 2. In an internal combustion engine having at least one electromagnetic fuel injector and a solenoid for actuating said injector in response to control signals of duration corresponding to the desired amount of fuel to be injected, an improved electric circuit for correcting the amount of fuel injected during each control signal comprising: a. a first resistance, one end of which is connected to one terminal of the solenoid; b. an adjustable potentiometer including a second resistance and a slider, the slider being connected to the other end of said resistance; c. a first diode connected between one end of the second resistance and the other terminal of the solenoid in a direction such that it shunts a portion of the solenoid energizing current to delay opening of the injector; and d. a second diode connected between the other end of the second resistance and the other terminal of the solenoid in a direction opposite to that of the first diode such that it shunts a portion of break-induced current in the solenoid to delay closing of the injector, the relative amount of opening and closing delay being determined by the position of the slider relative to the two ends of the second resistance. 